ปัญหาใช้ InputStream อ่านค่าจาก HttpServletRequest บน Servlet ไม่ได้

ลองอ่านตรง กับอ่านผ่าน BufferedReader ก็ไม่ได้
ทดสอบ debug พบว่ารองที่สอง ค่าของ InputStream.read() จะจำค่าครั้งก่อนไว้ คือเป็น -1 ทำให้ไม่อ่านข้อมูลในครั้งหลังๆ

ใครทราบแนวทางแก้ไข แนะนำหน่อยครับ



package com.mmm.servlet.test;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.io.InputStreamReader;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletInputStream;

import org.w3c.dom.Element;
import com.mmm.util.DOMUtil;


/**
* Servlet implementation class for Servlet: TestServlet
*
*/
public class TestServlet extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
static final long serialVersionUID = 1L;

/* (non-Java-doc)
* @see javax.servlet.http.HttpServlet#HttpServlet()
*/
public TestServlet() {
super();
}

/* (non-Java-doc)
* @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(request,response);
}

/* (non-Java-doc)
* @see javax.servlet.http.HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub


//StringBuffer outstr = readXML2(request);
//response.getWriter().println(outstr.toString());

//outstr = readXML2(request);
//response.getWriter().println(outstr.toString());

//Element root = DOMUtil.toDOM((InputStream)request.getInputStream());
//String txid = DOMUtil.getValue(DOMUtil.findTag(root, "txid"));


response.getWriter().println(request.getQueryString());
ServletInputStream in = request.getInputStream();
int i = in.read();







}
private StringBuffer readXML2(HttpServletRequest request){


StringBuffer sbuf = new StringBuffer();
try{
//ServletInputStream si=(ServletInputStream)request.getInputStream();
InputStream si=(InputStream)request.getInputStream();
boolean bl =si.markSupported();

int i=si.read();
while(i!= -1){
sbuf.append((char)i);
i=si.read();
}
}catch(IOException e){

}

return sbuf;



}

private StringBuffer readXML(HttpServletRequest request){
StringBuffer stringBuffer = new StringBuffer();

try{

InputStream inStream = (ServletInputStream)request.getInputStream();
//ServletInputStream inStream = (ServletInputStream)request.getInputStream();




BufferedReader requestData = new BufferedReader(new InputStreamReader(inStream));

String line = "";
try{
while ((line = requestData.readLine()) != null)
{
stringBuffer.append(line);
}


} catch (Exception e){
//response.getWriter().println("e1");
stringBuffer.append("error1");
}finally{
//inStream.close();
//requestData.close();
}
}catch(Exception e){
stringBuffer.append("error2"+e.getMessage());
}
return stringBuffer;

}


}